With respect to improved green strength, British Pat. No. 1,587,100 discloses an improved method for processing synthetic green strength polymers. The method for processing basically entails two mixing steps, the first being the mixing of the non-green strength polymer with carbon black and other compounding additives except the cure active ingredients, and the second mixing step being the mixing of the contents of the first mixture with the green strength polymer, cure active ingredients and other compounding ingredients. The green strength polymer is preferably a polymer such as styrene-butadiene containing bound tertiary amine groups which have been reacted with a dihalogen compound to form quaternary ammonium salts.
Another patent directed toward improved green strength is U.S. Pat. No. 3,827,991 which discloses a rubber composition exhibiting improved green strength which comprises 3 to 50 percent by weight of a 1,2-polybutadiene having a 1,2 addition unit content of 70 percent or higher and crystallinity of 5 percent or higher and 97 to 50 percent by weight of at least one conjugated diene-based rubbery polymer selected from the group consisting of styrene-butadiene copolymer rubber, polyisoprene rubber, natural rubber, acrylonitrile-butadiene copolymer rubber and polychloroprene rubber.
Another patent directed toward green strength improvement is U.S. Pat. No. 4,316,825 which discloses that the green strength of styrene-butadiene rubber, styrenebutadiene rubber/polybutadiene, natural rubber and blends thereof can be improved by blending with EPDM or EPM having a high degree of crystallinity.
With respect to the use of halogenated polymers in a rubber skim stock, U.S. Pat. No. 4,267,079, owned by the Assignee of record, discloses that the addition of Neoprene, a halogenated polymer, will improve adhesion and adhesion retention properties between the rubber skim stock and the metallic reinforcement. The addition is also disclosed as improving modulus properties of the cured rubber composition.
While others have described various methods of improving green strength and also the use of halogenated polymers, the employment of halogenated polymers to improve green strength has not been described in any patents or publications of which I am aware.